A Windows Phone handset produced by Samsung recently surfaced on GFX benchmark with the model number SGH-I187, and now it has reached the US Federal Communications Commission with GSM, HSPA and LTE frequencies.

The FCC filing indicated only that the handset sports AT&T-compatible frequencies, but the SHG-I187 model name that previously appeared in the GFX benchmarks suggested it runs the Windows Phone OS by Microsoft.

The benchmarks also revealed the SHG-I187 offers a 720-by-1,280-pixel resolution, as well as an Adreno 305 GPU and Qualcomm Snapdragon 400. Although, it could have a Qualcomm Snapdragon S4 Play or S4 Plus.

Many reports assumed that the SGH prefix in the model number meant it was likely to be bound for AT&T and T-Mobile in the US. We now know this could be the case (at least for AT&T), thanks to the FCC filing.

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So it appears as though Samsung is readying a mid-range handset that will help bulk Microsoft's Windows Phone lineup and run on AT&T networks. But that's about all we know for now, so stay tuned for more.